A city looks for big solutions in little – very little – houses

The 420 sq ft cottage in Karen Chapple's backyard boasts six "rooms". Photo: New Avenue.

On Saturday, Mayor Tom Bates will cut the ribbon on a new home on Delaware Street in Berkeley. It’s not every day a city leader takes the time to welcome a new dwelling into his fold, and this home is not big, nor particularly special; in fact it’s positively diminutive at just 420 sq ft, and can rightfully be described as a backyard cottage. So one might wonder why it warrants an “opening party” with dignitaries in attendance, sponsors — even a salsa band.

The reason is that small secondary units like this one — also known as in-law units, studios, or accessory buildings — represent a solution to a key challenge facing many cities: how to house a swelling population affordably without resorting to creating unsustainable suburban sprawl. “Smart growth”, in other words.

And Berkeley has decided to focus on these little houses. “We favor increasing the number of secondary units. It’s the only goal we have added to the housing element part of our general plan this year,” says Debra Sanderson, Planning Manager at the City of Berkeley.

The Delaware St cottage includes distinct areas for living, cooking, eating, working, bathing and sleeping. Photo: New Avenue.

These types of buildings often appeal to homeowners looking for more space without the need to relocate, or seeking rental income, and for home buyers looking for small, inexpensive urban homes on a permanent or semi-permanent basis.


The cute, zero-energy cottage at 934 Delaware Street was built by Berkeley start-up New Avenue, a company conceived at UC Berkeley which is where the cottage’s owner, Karen Chapple, also works.

It was while taking Dr. Ashok Gadgil’s Design for Sustainable Communities course at the Haas School of Business that Kevin Casey began to explore the idea of building a business around secondary units. He was spurred on by legislation in a number of states which decrees that most homeowners have the right to build a secondary unit on their property –and also by his student team’s own research.

“When we did a study of homes within half a mile of north Berkeley BART we found that 560 of the homes qualified for secondary units,” he said. Casey also figured out that almost the entire projected housing demand in California could be achieved by building accessory dwellings on existing properties. “That’s the point when I thought: this is a business,” he says.

Chapple became New Avenue’s first client when the student group came to see her at Cal — where she is Associate Professor of City & Regional Planning –to discuss their research. “I’ve always wanted to do one of these. I’m a New Yorker and I like density. When I look around Berkeley I  think it would look nicer with more buildings,” she says.

While Chapple concedes not every Berkeley resident would agree with her view — “there is a strong anti-growth contingent here,” she says — she sees backyard cottages as an exciting proposition in terms of a distributed housing model. “They are an asset-building strategy for Berkeley residents at the same time as a possible affordable housing strategy,” she says.


The cottage's loft sleeping area. Photo: New Avenue.

The Haas students used Chapple’s lot as a class project and it wasn’t long before she had refinanced her home to raise the $100,000 needed to build the sustainable cottage, the cost of which includes the zoning and building permits (see a breakdown of costs here). The house, which was designed by architect Mark Creedon, took three months to build and will run on solar power, will be used in a variety of ways: as a rental unit, to accommodate Chapple’s “constant stream of visitors”, and, if she has the luxury of not needing to use it for income, as an office.

Meanwhile, Sanderson is going to be examining ways to make it easier for more Berkeley residents to have their own little — or not so little — backyard pad (New Avenue has a number of different models on offer, some with two bedrooms, and double garage conversions can produce relatively spacious studios) . “We favor them because they address a number of social problems,” says Sanderson — “such as providing for ageing relatives and keeping communities stable and diverse.” She adds: “They also allow housing on a smaller scale in transit corridors.”

While zoning ordinances mean most homeowners have the right to build a secondary unit in Berkeley, they do need to meet pre-set criteria to qualify, including having one parking space, a minimum lot size and certain set-back requirements. One reason Berkeley has many illegal secondary units is that it’s not always easy to check all the boxes. Working with Chapple’s UC department, Sanderson plans to scrutinize each element of the process. “We are considering what we can change to facilitate the process,” she says.

Roll on tiny houses of the future.